Permeability of Sand-Based Cemented Backfill under Different Stress Conditions: Effects of Confining and Axial Pressures

Zhu, Cunli; Zhang, Jixiong; Zhou, Nan; Meng, Lingkui; Guo, Yaben

doi:10.1155/2021/6657662

Cited by 8 publications

(3 citation statements)

References 33 publications

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“…Water saturation is a key factor affecting the relative permeability characteristics of water–gas. The distribution of gas and water in the pore space will change as the water saturation changes, and the distribution of water content saturation is mainly directly affected by factors such as porosity and pore pressure [ 32 , 33 ].…”

Section: Resultsmentioning

confidence: 99%

Experimental Investigation of the Effect of Groundwater on the Relative Permeability of Coal Bodies around Gas Extraction Boreholes

Pang

Pan

Zhang

et al. 2022

IJERPH

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Water infiltration in boreholes is a common problem in mine gas pre-extraction, where water infiltration can significantly reduce the efficiency of gas extraction and curtail the life cycle of the borehole. It is important to evaluate the effect of groundwater on the permeability of the coal body around a gas extraction borehole. In order to determine the seepage parameters of the fractured coal body system around the borehole, a water–gas two-phase seepage test was designed to determine the relative seepage parameters of the fractured coal media seepage system. The main conclusion is that the relative permeability of gas can be effectively increased by increasing the negative extraction pressure at the early stage of extraction to accelerate drainage to reduce the water saturation of the coal seam. Under the combined effect of porosity and seepage pressure, the relative permeability of gas and water in the fractured coal rock body shows three stages. The dependence of the total permeability on the effective stress is closely related to the stages in the evolution of the pore structure, and the total effective permeability decreases with the increase in the effective stress. A decrease in porosity can lead to a decrease in permeability and an increase in the non-Darcy factor. Through an in-depth analysis of the damage and permeability pattern of the coal body around the perimeter of the dipping borehole, the efficient and safe extraction of gas from dipping boreholes in water-rich mines is thus ensured.

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Section: Resultsmentioning

confidence: 99%

Experimental Investigation of the Effect of Groundwater on the Relative Permeability of Coal Bodies around Gas Extraction Boreholes

Pang

Pan

Zhang

et al. 2022

IJERPH

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“…With the implementation of the Belt and Road Initiative, calcareous sand, biogenic sediment and skeletal remain of marine organism, has been a topic of interest among geotechnical researchers recently [1,2]. It is widely distributed in the continental shelf and coastline of tropical and subtropical climate between north and south latitude 30 degrees, such as the eastern and western of the Caribbean Sea, the Pacific Islands, the western of the Indian Ocean, and Nansha Islands and Xisha Islands in the South China Sea [3,4].…”

Section: Introductionmentioning

confidence: 99%

Undrained Cyclic Response and Resistance of Saturated Calcareous Sand considering Initial Static Shear Effect

Guo

Zhou

et al. 2021

Geofluids

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Sand elements in the natural or manmade field have often undergone initial static shear stresses before suffering cyclic loading. To explore the effect of static shear stress, a series of undrained cyclic triaxial tests were performed on dense and loose calcareous sand under different initial and cyclic shear stresses. The triaxial test results are used to describe the effect of static shear stress on the cyclic response of the calcareous sand with different relative density. Cyclic mobility, flow deformation, and residual deformation accumulation are the three main failure modes under varying static and cyclic shear stress levels. The cyclic resistance of dense sand is greater than that of loose sand, but the initial static stress has different effects on the cyclic resistance of the two kinds of sand. The dense sand owns a higher cyclic resistance with SSR increasing, while for the loose sand, 0.12 is the critical SSR corresponding to the lowest value of the cyclic resistance. The dense sand has more fast accumulation of dissipated energy, compared with loose sand. Additionally, an exponential relationship is established between static shear stress, relative density, and normalized energy density.

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“…Rib spalling and roadway floor heaving are more likely to occur under higher in situ stress, and reduce the service life of the roadway and coal mine [14][15][16]. Reinforcement by shotcreting using concrete-based material is the conventional method to address the problems of rib spalling and roadway floor heaving [17,18]. Concrete is mainly composed of such natural resources as river sands, gravel, and cement.…”

Section: Introductionmentioning

confidence: 99%

Effect of Doped Glass Fibers on Tensile and Shear Strengths and Microstructure of the Modified Shotcrete Material: An Experimental Study and a Simplified 2D Model

et al. 2021

Self Cite

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Shotcrete material has found extensive applications as a reinforcing material in the engineering sector. This study examined the effect of doped glass fibers on the mechanical performance of the modified shotcrete material composed of aeolian sand, fly ash, cement, quicklime, and doped glass fibers. Its tensile and shear strengths values were experimentally determined via a WAW-1000D computerized hydraulic universal tensile testing machine. Its microstructure was analyzed via a size analyzer, scanning electron microscope (SEM), and X-ray diffractometer (XRD). A 2D simplified mechanical model was elaborated to reflect the influence mechanism of the doped glass fibers on the mechanical performance of the modified shotcrete material. The experimental and mechanical analysis results indicated that, at the macroscopic scale, the experimental tensile and shear strengths of the shotcrete material doped with glass fibers were significantly higher than those of the undoped shotcrete material (by up to 310% and 596%, respectively). These results were in concert with the proposed model predictions, where the compound stresses in the shotcrete material were derived as the sum of the stress borne by the shotcrete material itself and the bridging stress exerted by the glass fibers. At the microscopic scale, SEM observations also revealed that the glass fibers were intertwined with each other and tightly enveloped by the shotcrete material particles within the modified shotcrete specimens, connecting the particles of different components into a whole and improving the overall mechanical strength. In addition, the relationships of the compound stress of the shotcrete material vs. embedment length, embedment angle, and cross-sectional area of the glass fibers were established. The research findings are considered instrumental in clarifying the mechanism by which the glass fibers influence the mechanical performance of shotcrete materials and optimize their solid waste (fly ash and quicklime) utilization.

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Permeability of Sand-Based Cemented Backfill under Different Stress Conditions: Effects of Confining and Axial Pressures

Cited by 8 publications

References 33 publications

Experimental Investigation of the Effect of Groundwater on the Relative Permeability of Coal Bodies around Gas Extraction Boreholes

Experimental Investigation of the Effect of Groundwater on the Relative Permeability of Coal Bodies around Gas Extraction Boreholes

Undrained Cyclic Response and Resistance of Saturated Calcareous Sand considering Initial Static Shear Effect

Effect of Doped Glass Fibers on Tensile and Shear Strengths and Microstructure of the Modified Shotcrete Material: An Experimental Study and a Simplified 2D Model

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